2018.5 Seneca – S2RV Chassis Wind Noise Fix

[dramo77355]

Wind noise in a 2018.5 Seneca – S2RV chassis.

Our new Seneca had a lot of cabin noise mostly linked to wind whistling at levels so loud that it inhibited conversations. When we purchase our Seneca, I had read that there were a few things that could help like plug the mirror bracket holes. I felt a door adjustment would, and it did help a bit.

Here are my steps to resolve the issues:

1. Had the dealer plug the mirror bracket holes prior to picking the Seneca up. I later added plugs to all the mirror bracket holes.
2. Went to the local Freightliner dealer in Bryan, Tx and they adjusted the doors – they did a great job and were wonderful to work with. - Minor Improvement.
3. Went a on a trip and used tape on the outside doors to try and reduce the noise. No improvement. This is when I discovered that the source of the noise was not the doors, and since I have already covered all the door related problems, I knew there was another source that HAD to be found.

Went nuclear and did the following:
• It appeared the noise was around the dash level of the front.
• The side cowling in front of the door is fiberglass and is not a great fit – Blue arrow (Photo -Seneca 1).
• Both sides have a gap on the top as well. I ran a bead of RTV just in case – Green Arrow (Photo - Seneca 2).
• I opened the door and opened the hood and looked to see if there was light coming from the front (engine compartment) – on yes, plenty of light.
• Plenty of small air leaks and potential whistles.
o Using black RTV, I sealed all openings until there was no light seen through the door opening looking forward to the engine. One large opening at the top required a piece of insulation prior to applying the RTV – a big opening.
• The yellow arrow (Photo - Seneca 3) shows that the bottom flap of the fiberglass cowling does not have a screw to hold it, and the cowling can move in the wind. I bolted it to the bottom piece. The lower piece has an indenture formed in the fiberglass where a nut should be (this can be seen by looking in the wheel well, but no bolt or nut was in place. Secured these pieces with a small bolt and nut - you can look in the wheel well to see where to drill your hole (NO more flapping in the wind). I had noticed that the wind noise varied with wind direction and could have been the result of this piece fluttering a bit due to wind. I also put an RTV seal on the bottom of the cowling - outside. It is not possible to put it on the inside due to space.
• Used RTV around loose rubber fitting on the windshield – lower drivers and passenger’s sides.
• Used RTV around the top of the doors to cover the gaps of the original door rubber strip covering the window.
• I used RTV for the gap between the mirror top mount long gap – bracket and the actual mirror arm (Red Circle in Photo - Seneca 4). I had previously plugged and RTVed the holes – some improvement.
• Removed the antenna – capped the stud with a plastic cap. Installed a whip antenna on the mirror bracket – I hope this provides better reception.

The cab is now quiet! A BIG difference.

The issue related to my fix is that I made all the modification at one time and cannot validate which specific modification cured the problem. I feel that sealing the gaps on the front cowling (in front of the doors) was the primary fix, with each of the other gaps contributing a little to the wind noise. We just finished a 4-hour trip with an exceptionally quiet cab that allowed us to have good conversations.

[Bruceter]

Nice write up on the wind noise issues.
I picked up the mirror plugs at Lowe’s but they only had enough for one door. So waiting to do the rest. I’ll have a look at the other areas you mentioned, not sure whether the m2 chassis would the same lower areas as your S2RV chassis

Bruce

[Bruceter]

Well after plugging all of the mirror bracket holes the whistling noise is still there, maybe a slight difference but not much.
Looks like I will have to look into these other areas and sealing them off.

Bruce

[Rustynuts]

I need to check over my cowl....can always have it quieter.

[Ender on the road]

Great write up. I have simply covered the holes in the mirrors with gorilla tape. That calmed most of my cab noise down. I still get a whistle and will look into the same places you have in my 2019 37RB

[RTVing]

Originally Posted by Bruceter

Nice write up on the wind noise issues.
I picked up the mirror plugs at Lowe’s but they only had enough for one door. So waiting to do the rest. I’ll have a look at the other areas you mentioned, not sure whether the m2 chassis would the same lower areas as your S2RV chassis

Bruce

Hi Bruce can you tell me specifically what the plugs are called or suppose to be used for that you got at Lowe's? Would love to pick those up but have no idea what to ask for.

[Bruceter]

Originally Posted by RTVing

Hi Bruce can you tell me specifically what the plugs are called or suppose to be used for that you got at Lowe's? Would love to pick those up but have no idea what to ask for.

I got them at Lowe’s. They are made by Hillman and they are called “nylon hole plugs” I have forgotten how many of each size you need, but you need 9/16” and 3/4”. I used a small amount of silicone sealer to help hold them in.
Hope this helps

Bruce

[RTVing]

So helpful!! Have spent too much time roaming isles. Tried the earplug method but wont stay in and proved to us it did make a difference.

[Rustynuts]

First let me say Dramo.....THANK YOU!! This is a huge noise reduction fix!

So I finally took the time to look at this cowl/side cover. The wind rushing behind this panel ends up coming right into the front of the door and then would blow out between the panel/door gap creating wind noise. I approached it a little different as this panel is only held on with 4 bolts and once they are removed, the panel slips right out. I had some very soft 1” thick weather stripping that I doubled up so when the panel was put back on, the panel compressed it making a very good seal. Then where the panel overlaps the cab areas I put a bead of clear silicone, filled any small voids with silicone then attached the panel and cleaned up any silicone that oozed out. There was a small area where the small inner fender meets the cab and the cowl piece and I filled in this area with silicone. Headed out today and immediately noticed a dramatic decrease in noise, the whooshing sound that I thought was from the mirrors is almost gone. It was very easy to carry on a conversations and I could hear the stereo!

On our last trip I used a decimeter on my phone going down the Freeway at 65 mph and it averaged 84-90 dB and today even going into a headwind, it was at 72-77 dB....a noticeable difference.

Thanks again Dramo for coming up with this and letting us know. I highly recommend doing this Nd even removing the panel it took about an hour to do both sides.

[dramo77355]

I glad the fix worked for you. We took a trip last week and my wife commented that we can now have a conversation in the cab. I probably over did it by sealing around the windows as well as the cowling. I know you should do make one change and then test, but I did all the changes at once to get the desired noise reduction. The wind noise was the only real issue I had with our Seneca, so now I have no complaints and love driving this RV.
Glad to have helped.

[SFM]

Great tips and pictures on everyone’s part. I am picking up our 2019 TS in the morning. I have not seen the unit or driven a newer model. Do you think the folks at Freightliner would have made any changes on the 2019 units??? First stop may very well be Lowe’s for Hillman plugs and silicone.

[Rustynuts]

I highly doubt any changes were made by Freightliner. The time to do this mod is well with it IMO.

[dramo77355]

To check for potential wind noise problems, open the hood, open the drivers door and look forward through the door jam to see if you can see light coming in from the engine bay. If you see light showing through from the engine bay, you will have the noise problem. I agree that Freightliner probably did not fix these problems wiht the latest release of trucks.

I had my Seneca in at the Freightliner dealer last week for service and I told the service manager how I had fixed the wind problem. He took pictures and was planning to use this for to help all the customer with their wind noise - both RV and truck.

[Rustynuts]

I think it could be fixed by them placing a thick foam panel to the back side of the plastic panel. If it was custom fitted and had good compression it could be a simple fix. I am not sure all the silicone is needed but figured it wouldn’t hurt while I had it off. I believe it’s juat the wind coming through that panel and hitting the front of the door causing the noise.

[RVermont]

Thanks guys. I picked up the foam and sealant this afternoon. Fixing it tonight. Got the love this site. At least this one is fairly cheap not like some of the mods.

[SFM]

Originally Posted by Rustynuts

I highly doubt any changes were made by Freightliner. The time to do this mod is well with it IMO.

Freightliner has not made any changes. High pitch whistle at 45 mph or better. Within 1 hour of picking up the coach I diverted to Rush Truck Center for a check engine light/code. Exhaust regen over heat sensor. 3 other Seneca units there for the same issue. There is a lot of squeaking from the front fiberglass cap and truck cab connection. Do others have the same squeaks??

[dramo77355]

This is most likely the main slide (living room) net to the drivers door. When you open it out at home, put some lube on the rubber gasket seal and wax the fiberglass beneath the location of the rubber seal. Ours stopped squeaking the first time we got big rain while camping and the rain lubed the seal enough to make it quit squeaking on the drive home.

[TerrenceB]

Originally Posted by dramo77355

Wind noise in a 2018.5 Seneca – S2RV chassis.

Our new Seneca had a lot of cabin noise mostly linked to wind whistling at levels so loud that it inhibited conversations. When we purchase our Seneca, I had read that there were a few things that could help like plug the mirror bracket holes. I felt a door adjustment would, and it did help a bit.

Here are my steps to resolve the issues:

1. Had the dealer plug the mirror bracket holes prior to picking the Seneca up. I later added plugs to all the mirror bracket holes.
2. Went to the local Freightliner dealer in Bryan, Tx and they adjusted the doors – they did a great job and were wonderful to work with. - Minor Improvement.
3. Went a on a trip and used tape on the outside doors to try and reduce the noise. No improvement. This is when I discovered that the source of the noise was not the doors, and since I have already covered all the door related problems, I knew there was another source that HAD to be found.

Went nuclear and did the following:
• It appeared the noise was around the dash level of the front.
• The side cowling in front of the door is fiberglass and is not a great fit – Blue arrow (Photo -Seneca 1).
• Both sides have a gap on the top as well. I ran a bead of RTV just in case – Green Arrow (Photo - Seneca 2).
• I opened the door and opened the hood and looked to see if there was light coming from the front (engine compartment) – on yes, plenty of light.
• Plenty of small air leaks and potential whistles.
o Using black RTV, I sealed all openings until there was no light seen through the door opening looking forward to the engine. One large opening at the top required a piece of insulation prior to applying the RTV – a big opening.
• The yellow arrow (Photo - Seneca 3) shows that the bottom flap of the fiberglass cowling does not have a screw to hold it, and the cowling can move in the wind. I bolted it to the bottom piece. The lower piece has an indenture formed in the fiberglass where a nut should be (this can be seen by looking in the wheel well, but no bolt or nut was in place. Secured these pieces with a small bolt and nut - you can look in the wheel well to see where to drill your hole (NO more flapping in the wind). I had noticed that the wind noise varied with wind direction and could have been the result of this piece fluttering a bit due to wind. I also put an RTV seal on the bottom of the cowling - outside. It is not possible to put it on the inside due to space.
• Used RTV around loose rubber fitting on the windshield – lower drivers and passenger’s sides.
• Used RTV around the top of the doors to cover the gaps of the original door rubber strip covering the window.
• I used RTV for the gap between the mirror top mount long gap – bracket and the actual mirror arm (Red Circle in Photo - Seneca 4). I had previously plugged and RTVed the holes – some improvement.
• Removed the antenna – capped the stud with a plastic cap. Installed a whip antenna on the mirror bracket – I hope this provides better reception.

The cab is now quiet! A BIG difference.

The issue related to my fix is that I made all the modification at one time and cannot validate which specific modification cured the problem. I feel that sealing the gaps on the front cowling (in front of the doors) was the primary fix, with each of the other gaps contributing a little to the wind noise. We just finished a 4-hour trip with an exceptionally quiet cab that allowed us to have good conversations.

Outstanding detective work on your Seneca. Will definitely follow your lead! Question from a novice: what is RTV?

[TerrenceB]

Originally Posted by SFM

Great tips and pictures on everyone’s part. I am picking up our 2019 TS in the morning. I have not seen the unit or driven a newer model. Do you think the folks at Freightliner would have made any changes on the 2019 units??? First stop may very well be Lowe’s for Hillman plugs and silicone.

We purchased a 2019 a few months ago, with the same "whistling" wind issues, no correction by Freightliner yet... perhaps they have made some production changes of the latest Freightliner chassis. We had the Tampa Freightliner dealer check it out a few weeks ago, and they were not aware of the issues yet, blamed it on the chassis builder.

[TerrenceB]

Originally Posted by SFM

Great tips and pictures on everyone’s part. I am picking up our 2019 TS in the morning. I have not seen the unit or driven a newer model. Do you think the folks at Freightliner would have made any changes on the 2019 units??? First stop may very well be Lowe’s for Hillman plugs and silicone.

We purchased a 2019 a few months ago, with the same "whistling" wind issues, no correction by Freightliner yet... perhaps they have made some production changes of the latest Freightliner chassis. We had the Tampa Freightliner dealer check it out a few weeks ago, and they were not aware of the issues yet, blamed it on the chassis builder.